1. Field of the Invention
The present general inventive concept relates to an HDD (hard disk drive), and more particularly, to a unit to increase a floating force that lifts a slider in an inner disk region and an HDD having the same.
2. Description of the Related Art
A hard disk drive (HDD) is an apparatus that uses a slider having a magnetic head to record data or read data on or from a disk-shaped data storing medium. The HDD is generally used as an auxiliary memory in a computer, an MP3 player, a mobile phone, etc.
FIG. 1 is a schematic plane view illustrating one example of a conventional HDD 10.
With reference to FIG. 1, the HDD 10 includes a disk 20, which is a data storing medium, a spindle motor 15 rotating the disk 20 at high speed, and an HSA (head stack assembly) 25, all of which are mounted in a housing having a base member 11, which is covered by a cover member (not shown). A slider 27 having a magnetic head (not shown) to record or read data is mounted on a front end of the HSA 25, and the HSA 25 records data on the disk 20 or reads the data recorded on the disk 20 by moving the slider 27 to a predetermined position of the disk 20. An FPC (flexible printed circuit) bracket 35 is arranged at a corner of one side of the base member 11 in order to connect an FPC 32, which is connected to the HSA 25, with a main circuit substrate (not shown) positioned under the base member 11.
When the disk 20 rotates counter-clockwise at high speed on the base member 11, airflow is generated in the same direction as the rotation direction of the disk 20, thereby lifting the slider 27. Thus, the slider 27 floats at a predetermined height above the disk 20, since a force generated by the airflow is equal to an elastic force of the front end of the HSA 25 that biases the magnetic head toward the disk 20. When the slider 27 is in a floating state, the magnetic head thereof records or reads data on or from the disk 20.
In general, a surface region of the disk 20 where data is recorded may be divided into three regions in a radial direction including an inner region ID, a middle region MD, and an outer region OD. When the disk 20 rotates, a ratio of linear velocities in the inner region ID and the outer region OD of the disk 20 reaches 2.5 to 3, because of the difference in the distances from a rotation center C. The difference between the linear velocities in the inner region ID and the outer region OD causes a difference between speeds of the airflow in the inner region ID and the airflow in the outer region OD, thereby reducing the floating force of the slider 27 when the slider 27 moves to the inner region ID. Consequently, as the floating state of the slider becomes unstable, the slider 27 and the disk 20 may collide with each other. For example, the slider 27 and the disk 20 can collide with each other even when a small external impact is applied to the HDD 10. As a result, a possibility of damaging the disc 20 and the magnetic head increases. The effects of this unstable floating state of the slider 27 are greater in a small-sized HDD with a diameter of 1 inch or less, where the rotation velocity of the disk 20 is relatively low.